A semiconductor device and a process of forming the semiconductor device are disclosed. The semiconductor device type of a high electron mobility transistor (HEMT) has double SiN films on a semiconductor layer, where the first SiN film is formed by the lower pressure chemical vapor deposition (LPCVD) technique, while, the second SiN film is deposited by the plasma assisted CVD (p-CVD) technique. Moreover, the gate electrode has an arrangement of double metals, one of which contains nickel (Ni) as a Schottky metal, while the other is free from Ni and covers the former metal. A feature of the invention is that the first metal is in contact with the semiconductor layer but apart from the second SiN film.

A method of fabricating transistors with short gate length by two-step photolithography is provided. This method utilizes the two-step photolithography by a stepper as well as controlling a first exposed position and a second exposed position to change the gate length.

A semiconductor device and a manufacturing method thereof are provided. The semiconductor device includes a substrate, a first channel layer, a first barrier layer, a gate electrode and an insulating structure. The substrate has a recess, and the first channel layer, the first barrier layer, the gate electrode and the insulating structure are disposed in the recess. The first channel layer covers a surface of the recess. The first barrier layer is disposed on a surface of the first channel layer. A surface of a bottom portion of the first barrier layer is covered by the gate electrode, and a top surface of the gate electrode is lower than a topmost surface of the substrate. Surfaces of the gate electrode and a top portion of the first barrier layer are covered by the insulating structure.

A process to form a HEMT can have a gate electrode layer that initially has a plurality of spaced-apart doped regions. In an embodiment, any of the spaced-apart doped regions can be formed by depositing or implanting p-type dopant atoms. After patterning, the gate electrode can include an n-type doped region over the p-type doped region. In another embodiment a barrier layer can underlie the gate electrode and include a lower film with a higher Al content and thinner than an upper film. In a further embodiment, a silicon nitride layer can be formed over the gate electrode layer and can help to provide Si atoms for the n-type doped region and increase a Mg:H ratio within the gate electrode. The HEMT can have good turn-on characteristics, low gate leakage when in the on-state, and better time-dependent breakdown as compared to a conventional HEMT.

A method includes providing a semiconductor structure including: a substrate; a layer stack with each layer of the layer stack including a Group III-nitride material; and a p-type doped GaN layer on the layer stack. The method also includes providing, on the GaN layer, a metal bi-layer including a first metal layer in contact with GaN layer and a second metal layer on the first metal layer and having a lower sheet resistance than the first metal layer. The method also includes performing a patterning process upon the metal bi-layer and the p-type doped GaN layer such that a first periphery of the first metal layer is aligned to a second periphery of the second metal layer and such that a first cross section of the metal bi-layer is smaller than a second cross section of the GaN layer parallel to the first cross section.

An HEMT includes a first III-V compound layer. A second III-V compound layer is disposed on the first III-V compound layer. The composition of the first III-V compound layer is different from that of the second III-V compound layer. A gate is disposed on the second III-V compound layer. The gate includes a first P-type III-V compound layer, an undoped III-V compound layer and an N-type III-V compound layer are deposited from bottom to top. The first P-type III-V compound layer, the undoped III-V compound layer, the N-type III-V compound layer and the first III-V compound layer are chemical compounds formed by the same group III element and the same group V element. A drain electrode is disposed at one side of the gate. A drain electrode is disposed at another side of the gate. A gate electrode is disposed directly on the gate.

In some embodiments, the present disclosure relates to a semiconductor device. The semiconductor device includes a channel layer disposed over a base substrate, and an active layer disposed on the channel layer. A source contact and a drain contact are over the active layer and are laterally spaced apart from one another along a first direction. A gate electrode is arranged on the active layer between the source contact and the drain contact. A passivation layer is arranged on the active layer and laterally surrounds the source contact, the drain contact, and the gate electrode. A conductive structure is electrically coupled to the source contact and is disposed laterally between the gate electrode and the source contact. The conductive structure extends along an upper surface and a sidewall of the passivation layer.

An HEMT device of a normally-on type, comprising a heterostructure; a dielectric layer extending over the heterostructure; and a gate electrode extending right through the dielectric layer. The gate electrode is a stack, which includes: a protection layer, which is made of a metal nitride with stuffed grain boundaries and extends over the heterostructure, and a first metal layer, which extends over the protection layer and is completely separated from the heterostructure by said protection layer.

An electronic device can include a gate structure. In an embodiment, the gate structure can include a gate electrode including a doped semiconductor material, a metal-containing member, a pair of conductive sidewall spacers. The first metal-containing member can overlie the gate electrode. The conductive sidewall spacers can overlie the gate electrode and along opposite sides of the first metal-containing member. In another embodiment, the gate structure can include a gate electrode, a first metal-containing member overlying the gate electrode, and a second metal-containing member overlying the first metal-containing member. The first metal-containing member can have a length that is greater than the length of the second metal-containing member and substantially the same length as the gate electrode.

An HEMT includes a first III-V compound layer. A second III-V compound layer is disposed on the first III-V compound layer. The composition of the first III-V compound layer is different from that of the second III-V compound layer. A gate is disposed on the second III-V compound layer. The gate includes a first P-type III-V compound layer, an undoped III-V compound layer and an N-type III-V compound layer are deposited from bottom to top. The first P-type III-V compound layer, the undoped III-V compound layer, the N-type III-V compound layer and the first III-V compound layer are chemical compounds formed by the same group III element and the same group V element. A drain electrode is disposed at one side of the gate. A drain electrode is disposed at another side of the gate. A gate electrode is disposed directly on the gate.